// JavaScript Document<script language="javascript">
          
  /*登陆*/  
  function valid(){
     var name = document.getElementById("username").value;
     var pass = document.getElementById("password").value;
     if(name==""){
        alert("账号不能为空");
        return false;
     }
     if(pass==""){
        alert("密码不能为空");
        return false;
     }
     return true;
   }
   
   